Although I mention parents specifically in the title, this isn’t just for parents to respond.
My wife and I are trying to raise our child to be bilingual (English and Portuguese). Currently we’re both speaking a bit of both to our child and when they eventually go to school we’ll speak more Portuguese as they’ll be exposed to English everywhere else.
Is this a good approach or is there something we can do better?
Not a parent, but I was raised bilingually in English and German, while growing up in Germany.
My Dad (almost) always speaks English with me, and my Mom (almost) always speaks German with me, even to this day at age 31. This approach worked well for us and I'm fluent in both languages, but I can imagine an approach where both parents speak both languages could work as well.
What also really helped me was to consume a lot of media in English, so maybe you could encourage your child to do that as well.
I wasn’t raised bilingual but consuming Portuguese media helped me learn really quickly (just over a year to be at a comfortable conversational level).